1. Field of the Invention
The present invention relates to a ball-jointed bearing arrangement of the piston heads in an axial piston machine within a drive flange wherein a bearing member formed of a material with good antifriction properties for receiving a piston head is seated in a recess of the drive flange whereby all bearing members are covered by a covering plate which is detachably fastened to the drive flange.
2. Discussion of the Prior Art
Since the piston heads of the piston rod, and the drive flange which receives these, are subjected to a high load during operation, they were originally produced from a highly wear-resistant material, such as hardened steel, preferably nitrided steel. Warping is produced as a result of the hardening of the drive flange. The spherical indentations in the drive flange which conform to the configuration of the piston head, thus required extremely precise prefinishing with respect to shape and surface finish whereby, after hardening, there was still required a lapping process in order to remove the connecting zone, to improve the surface finish and to correct the ball shape (spherical indentation). The specific load is limited due to the non-optimized antifriction of steel on steel. In the event of the failure of one of the components, there is no possibility of reworking, as a result of which the drive flange and the piston must be completely replaced.
This problem could be solved through utilization of the ball-jointed bearing support of the above mentioned type, as disclosed in German patent specification No. 1 225 051. Cylindrical recesses were accordingly provided in the drive flange the side distant from the piston head; into which these were fitted or pressed two-part bearing members with a dividing line extending transverse to the longitudinal axis of the machine and formed of a material having good antifriction properties. The fitting in of one of these parts can only be effected subsequent to the insertion of the piston head. Finally, there is effected a covering of the drive flange by means of a detachably fastened covering plate on the side of the drive flange remote from the piston head. This will facilitate that the drive flange itself can be manufactured of a lower quality material than heretofore, whereas for the bearing members or the components thereof, there can be employed a material having good antifriction properties, such as a smooth bronze alloy. Upon the failure of these components, particularly those of the bearing member, these can then be exchanged in a simple manner. However, disadvantageous in these known ball-jointed bearings, in addition to the complicated assembly thereof is also that the drive flange is extensively weakened, in effect, the dimensions must be substantially increased in order to be able to conduct along the torque which is to be transmitted. The cylindrical bores in which the bearing members must be inserted must be prefinished extremely precisely. Due to the fitting in of the bearing member a deformation can occur, as a result of which a final finishing must be effected after insertion. This type of procedure is thus encumbered with high costs.